Which wood-cutting chisel requires being struck with a mallet?

The butt chisel is designed primarily for light work and does not require the use of a mallet for its operation. Instead, it's typically used for hand-held tasks, allowing for greater control and precision in fine woodworking.

In contrast, the mortising chisel is specifically made to handle the force of a mallet when creating mortises in wood. Its robust design and thicker blade allow it to withstand repeated striking. The framing chisel, also designed for heavier work, requires a mallet for driving the chisel into materials such as timber. The socket chisel, while able to be struck, doesn't typically need a mallet as part of its primary function.

In this case, the correct chisel that requires being struck with a mallet is actually the mortising chisel. These chisels are built to be struck for creating deeper, more precise mortises, making them ideal for joinery work where strength and precision are critical.